Anything red/black, gold or yellow and black, or lime green! Particularly halters, saddles, and bridles, and possibly boots, also made-to-order nameplate halters...all will make me drool and cry like a baby (because other people will probably beat me to buying! hehe!) Good luck with the grand opening!

Seconding the custom nameplate halters. Also... if I'm brave enough to mention it... some kind of booklet/kit/directions for making an English saddle. There are no good English saddle directions out there, and I would happily pay for one.